Vue.js实现不定高度模块垂直展开与收缩组件教程

本文介绍如何在Vue.js中实现一个支持垂直方向展开与收缩的不定高度模块组件。通过函数式组件结合CSS过渡动画，解决传统固定高度方案无法适应内容变化的问题，实现模块点击展开、再次点击隐藏的复用功能。

需求分析与难点

需求分析：

如图所示，存在大量高度不固定的模块（示例仅展示两个，实际项目包含十三个），需实现点击标题展开模块、再次点击隐藏模块的功能，并保证组件可复用。

点击红框前：

需求分析与难点

点击后：

需求分析与难点

难点分析:

模块高度不固定。例如，最初尝试的方法如下：


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .box{
      height:500px;
      background-color:black; 
       overflow: hidden;            
    }
    .mybox-leave-active,.mybox-enter-active{
      transition: all 1s ease; 
    }
    .mybox-leave-active,.mybox-enter{
      height:0px !important;
    }
    .mybox-leave,.mybox-enter-active{
      height: 500px;
    }
  </style>
</head>
<body>
<div id="box">
  <transition name="mybox">
    <div class="box" v-show="boxshow"></div>
  </transition>
  <button @click="togglebox">按钮</button>
</div>
</body>
<script src="../bower_components/vue/dist/vue.js"></script>
<script>
  new Vue({
    el:'#box',
    data:{
      boxshow:false
    },
    methods:{

      togglebox:function(){
        this.boxshow = !this.boxshow;
      }
    }   
  });
</script>
</html>

该方法虽能实现点击展开与收缩，但存在明显缺陷：限制了容器高度，要求每个模块固定高度，不符合实际需求场景。

解决方案与实现

解决方案：

1、实现一个函数式组件


本人命名为vertical-toggle.js
// Created by xiaoqiang on 17/04/2018.
const elTransition = '0.3s height ease-in-out, 0.3s padding-top ease-in-out, 0.3s padding-bottom ease-in-out'
const Transition = {
 'before-enter' (el) {
  el.style.transition = elTransition
  if (!el.dataset) el.dataset = {}
  el.dataset.oldPaddingTop = el.style.paddingTop
  el.dataset.oldPaddingBottom = el.style.paddingBottom
  el.style.height = 0
  el.style.paddingTop = 0
  el.style.paddingBottom = 0
 },
 'enter' (el) {
  el.dataset.oldOverflow = el.style.overflow
  if (el.scrollHeight !== 0) {
   el.style.height = el.scrollHeight + 'px'
   el.style.paddingTop = el.dataset.oldPaddingTop
   el.style.paddingBottom = el.dataset.oldPaddingBottom
  } else {
   el.style.height = ''
   el.style.paddingTop = el.dataset.oldPaddingTop
   el.style.paddingBottom = el.dataset.oldPaddingBottom
  }
  el.style.overflow = 'hidden'
 },
 'after-enter' (el) {
  el.style.transition = ''
  el.style.height = ''
  el.style.overflow = el.dataset.oldOverflow
 },
 'before-leave' (el) {
  if (!el.dataset) el.dataset = {}
  el.dataset.oldPaddingTop = el.style.paddingTop
  el.dataset.oldPaddingBottom = el.style.paddingBottom
  el.dataset.oldOverflow = el.style.overflow
  el.style.height = el.scrollHeight + 'px'
  el.style.overflow = 'hidden'
 },
 'leave' (el) {
  if (el.scrollHeight !== 0) {
   el.style.transition = elTransition
   el.style.height = 0
   el.style.paddingTop = 0
   el.style.paddingBottom = 0
  }
 },
 'after-leave' (el) {
  el.style.transition = ''
  el.style.height = ''
  el.style.overflow = el.dataset.oldOverflow
  el.style.paddingTop = el.dataset.oldPaddingTop
  el.style.paddingBottom = el.dataset.oldPaddingBottom
 }
}
export default {
 name: 'VerticalToggle',
 functional: true,
 render (h, { children }) {
  const data = {
   on: Transition
  }
  return h('transition', data, children)
 }
}

2、引用此组件

需求分析与难点